During the integrated circuit (IC) device manufacturing process, a specific percentage of IC devices are subject to a series of testing phases after the silicon dies are attached and electrically to printed circuit boards, thereby creating the IC devices. One of the final testing phases is burn-in, during which the internal core logic of the IC devices are exposed to heat and simultaneously activated with voltage levels that are significantly greater than design specifications. Burn-in typically last several hours at temperatures reaching 140° C. and voltage levels that are typically 40% higher than the IC device design specification, which usually has a tolerance of plus or minus five to ten percent.
Burn-in is performed in specially designed burn-in ovens that hold a plurality of printed circuit boards (PCBs) known as burn-in boards (BIBs), with each BIB holding a plurality of IC devices (typically 40 to 50) mounted in its own socket. Prior to installation, IC devices, also known as devices under test (DUTs) arrive from a fabrication plant in IC device delivery trays which typically hold more than 60 DUTs. An angled view of a section of a sample IC device delivery tray is shown in FIG. 1A. The IC device delivery tray, generally referenced 10, comprises IC device delivery tray section 12 and twenty one cavities 14. The cavities are recessed to hold the DUTs in place.
DUTs are positioned in the cavities of the IC device delivery tray with their contacts facing down (i.e. into the tray). A sample IC device is shown in FIG. 1B. The diagram, generally referenced 20, comprises IC device 22 with contacts 24.
Prior to burn-in DUTs transferred from an IC device delivery tray to a BIB via an autoloader. An autoloader is an electro-mechanical pick-and-place machine which removes an individual DUT from an IC device delivery tray and couples it to an available socket on the BIB. A block diagram illustrating an autoloader is shown in FIG. 2. The block diagram, generally referenced 30, comprises IC device delivery tray 32, autoloader 42 and BIB 44. DUTs 34, 36, 38, 40 arrive in IC device delivery tray 32 with their interface contacts resting on the IC device delivery tray (i.e. facing down). Autoloader 42 takes hold of the DUTs individually and installs them into sockets 46, 48, 50, 52 coupled to BIB 44.
There are inherent inefficiencies with transferring DUTs from an IC device delivery tray to a BIB. Since the autoloader transfers DUTs individually and the capacity of each BIB can be more than 50 DUTs, this is a lengthy process. In addition, the number of DUTs on an IC device delivery tray is generally greater than the number of DUTs to be installed on each BIB. Therefore more BIBs than Trays are required, which increases BIB production cost.
There are also inefficiencies with designing BIBs with sockets to hold the DUTs. The overhead of sockets in BIB designs impacts the size of the BIB and the size of the burn-in oven (each oven holds multiple BIBs). In addition, sockets are expensive, can only be used for a specific DUT design and have a limited lifespan.
Therefore, there is a need for a mechanism to transfer a plurality of DUTs from an IC device delivery tray to a BIB in a single step. For efficiency, the number of DUTs on the BIB should equal the number of DUTs in the IC device delivery tray. In addition, the BIB should be designed without using sockets. This reduces the cost and the size of the BIBs. Smaller BIBs enable the design of smaller burn-in ovens which further reduces costs due to smaller size, higher capacity and lower energy requirements per tested IC device.